Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden of disclosing behavior. It reveals the data source (Open-Meteo) but does not state that the operation is read-only, that non-city parameters are discarded, what the response looks like, or any error/rate-limit behavior. The schema descriptions hint at 'discarded after the shape check' behavior, but the description itself is silent.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no filler. It communicates the core function immediately. However, it is so terse that it omits important scope caveats, though conciseness itself is not the issue.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with nine optional parameters, no annotations, and no output schema, a one-sentence description is insufficient. It does not explain which parameter to use, what happens with the others, what the return value is, or how the Open-Meteo call behaves. An agent cannot confidently invoke this tool correctly based on the description alone.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all nine parameters. The description adds only the mention of 'city,' reinforcing the primary parameter, but it does not explain the role of the other eight parameters or warn that they are irrelevant to the weather use case. Baseline 3 applies because the schema carries the parameter documentation burden.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific function – returning current temperature for a city via Open-Meteo – which is clear in isolation. However, the input schema exposes eight additional parameters (ref, url, feed, host, json, path, zone, query) with no explanation of how they relate to weather, and the description does not clarify that only 'city' is relevant. This makes the tool's actual scope ambiguous and fails to differentiate it from sibling hint tools like geo-hint.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided about when to use this tool versus alternatives such as geo-hint or timezone. The description does not mention prerequisites (e.g., a valid city name), nor does it state that other parameters are ignored. An agent must infer the intended use case solely from the tool name.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.